Catheter placement units

ABSTRACT

A catheter placement unit comprises an introducing needle (2) having a pointed tip (6) for introducing a catheter (4) into a desired position in a patient&#39;s body, a needle hub (3) for mounting the needle (2) so that the needle extends through an axial bore in the catheter (4) during introduction of the catheter into the patient&#39;s body and so that the needle can subsequently be withdrawn from the catheter bore leaving the catheter in position in the patient&#39;s body, and a needle tip protector (10) on the needle for shielding the needle tip (6) when the needle has been withdrawn from the catheter bore. The needle tip protector (10) includes a guard element (16) which is held against a resilient bias in a cocked position to one side of the catheter (4) while the catheter is introduced into the patient&#39;s body and which, on subsequent withdrawal of the needle (2) from the catheter bore, is moved laterally by resilient action from the cocked position into a guard position in which it shields the needle tip (6). Thus the protector (10) reliably guards against needle stick injuries during withdrawal and subsequent disposal of the needle.

FIELD OF THE INVENTION

This invention relates to catheter placement units.

BACKGROUND OF THE INVENTION

It is established medical practice to introduce a flexible tubularcatheter into a desired position in a patient's body by means of acatheter placement unit which includes an introducing needle extendingexternally or internally of the catheter and projecting beyond the endof the catheter. In use of such a catheter placement unit to place acatheter within a patient's vein for supply of infusion fluid, forexample, the needle tip projecting beyond the end of the catheter servesto puncture the patient's skin and to locate the catheter within thevein. When the catheter is suitably positioned, as may be determined bythe flow of blood in the hub of the needle, the needle may be withdrawnleaving the catheter in position in the vein. Typically the needle iscompletely withdrawn from the catheter and safely disposed of prior tothe connection of a fluid line to the catheter so as to prevent damageto the patient by the needle during infusion. However the need towithdraw the needle from the catheter leads to a risk that doctors ornurses will accidentally prick themselves with the needle, and this canbe highly dangerous due to the risk of transfer of blood-relateddiseases.

U.S. Pat. No. 3,463,152 and U.S. Pat. No. 3,536,073 disclose catheterplacement units of a type in which the needle is withdrawn into ahousing connected to the catheter and locked therein after placement ofthe catheter in the patient's body, in order to prevent damage to thepatient from the needle. However such catheter placement units arecomplex and bulky in that they require a needle housing which remainsattached to the catheter in use, and are not suitable for use inapplications where the needle is to be withdrawn completely from thecatheter and disposed of.

U.S. Pat. No. 4,978,344 discloses a catheter placement unit of a type inwhich the needle is withdrawn completely from the catheter and disposedof after placement of the catheter in the patient's body, and in whichthe action of withdrawal of the needle from the catheter causes atethered cap portion to be drawn over the needle tip. However thedrawing of the cap portion over the needle tip relies on frictionalengagement of the cap portion by the catheter hub, and it is possible towithdraw the needle from the catheter without triggering the requiredcapping action. Also, because of the form of the capping portion, it ispossible for the needle tip to be re-exposed after capping.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a catheter placement unitwith means to reliably prevent needle stick injuries on withdrawal ofthe needle.

According to the present invention there is provided a catheterplacement unit as defined by the accompanying claims.

Since movement of the guard element into the guard position in use ofsuch a catheter placement unit occurs as a direct consequence ofwithdrawal of the needle from the catheter bore, it follows that theneedle tip is reliably protected by the guard element as soon as it iswithdrawn from the catheter bore, and there is no risk of the doctor ornurse or the patient being accidentally pricked by the needle afterwithdrawal. Furthermore the needle may be safely disposed of without anyadditional shielding measures being required.

BRIEF DESCRIPTION OF THE DRAWINGS

Although the catheter placement unit may be supplied for fitting to aseparately supplied assembly comprising a catheter and catheter hub, itis contemplated that the catheter placement unit supplied will generallyinclude a catheter and catheter hub to which the needle, needle hub andprotector are fitted ready for introduction of the catheter into thepatient's body.

In order that the invention may be more fully understood, reference willnow be made, by way of example, to the accompanying drawings, in which;

FIG. 1 is a side view of a catheter placement unit in accordance withthe invention in a partially disassembled condition;

FIG. 2 is an axial section through the catheter placement unit of FIG. 1when fully assembled, FIG. 2A showing a detail of the unit in the guardposition and FIG. 2B showing an end view of the unit; and

FIGS. 3 and 4 are side views of further catheter placement units inaccordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, the catheter placement unit 1 comprises anintroducing needle 2 mounted on a transparent plastics needle hub 3 inconventional manner, and a flexible tubular catheter 4 mounted on aplastics catheter hub 5 in conventional manner. The needle 2 extendswithin the catheter bore so that its pointed tip 6 projects from the endof the catheter 4. A plug 7 is optionally fitted into the end of thecatheter hub 5 for guiding the needle 2 within the catheter hub 5,although it is possible for this plug 7 to be omitted if the other partsof the assembly are suitably adapted. A vent filter 8 is fitted into theend of the needle hub 3, in conventional manner. Furthermore an annularflange 9 is provided on the end of the catheter hub 5.

In addition the catheter placement unit 1 includes a needle tipprotector 10 on the needle which is coupled to the needle hub 3 by aflexible plastics strap 11 slidingly extending through an apertured part12 of the needle hub 3. The protector 10 is positioned between theneedle hub 3 and the catheter hub 5 with the needle 2 extending througha bore 12A in a plastics body part 13 of the protector 10, and aresilient guard element 14 made of spring steel is mounted on the bodypart 13 by a tensioning part 15. As shown in FIG. 2, when the unit isfully assembled the tensioning part 15 holds a bent end portion 16 ofthe guard element 14 in engagement with the annular flange 9 on thecatheter hub 5 so as to retain the guard element 14 under tension in acocked position against the resilient bias imparted by the spring steel.The tensioning part 15 is hingedly connected to the body part 13 and ispivotable from an initial position (as shown in FIG. 1) during assemblyinto its tensioning position (shown in FIG. 2) in which it is held byprojections 17 which engage by snap action within corresponding recesses17A (shown in FIG. 2B) in the body part 13.

In use of the catheter placement unit 1 to position a catheter within apatient's vein, the patient's skin is punctured by the needle tip 6 andthe unit 1 is manipulated to place the needle tip 6 in the requiredposition as indicated by the presence of blood in the needle hub 3. Whenthe correct position is reached, the needle 2 is slowly withdrawn fromthe catheter bore by grasping the catheter hub 5 in one hand whilst theneedle hub 3 is moved by the other hand in the direction away from thecatheter hub 5 and the protector 10, the flexible strap 11 slidingwithin the apertured part 12 to permit such movement. When the needlehub 3 has been moved to a sufficient extent for the needle tip 6 to bewithdrawn from the catheter hub 5 and the plug 7, the needle 2 and theneedle hub 3 become detached from the catheter 4 and the catheter hub 5,and the guard element 14 is disengaged from the annular flange 9 on thecatheter hub 5 to permit it to move by resilient action into its guardposition protecting the needle tip 6, as shown in the detail of FIG. 2A.

Retention of the protector 10 on the needle 2 in this position isensured by the strap 11 which is prevented from further sliding withinthe apertured part 12 by virtue of a stop 18 on the end of the strap 11.The other end of the strap 11 is also preferably provided with a stop 19and is connected to the body part 13 of the protector 10 by extendingthrough a slot 20 in the body part 13. It is convenient for the slot 20and the corresponding slot in the apertured part 12 to have openings bymeans of which the strap 11 may be introduced into the slots from oneside during assembly.

FIG. 3 shows a catheter placement unit 30 which is generally similar tothe catheter placement unit 1 of FIGS. 1 and 2 except that it does notinclude the needle tip protector 10 and that it additionally includes aprotective cap 31 for the needle 2 and catheter 4. The protective cap 31is held on the unit 1 by a pivoting member 32 having fingers 33 whichengage flange formations 34 on the needle hub 3. In order to disengagethe protective cap 31 from the unit 30, the pivoting member 32 is simplypivoted in the direction of the arrow 35 by exerting a pushing force ona projecting flange 36 so as to place the pivoting member 32 in theposition shown in broken lines at 32' clear of the formations 34 on theneedle hub 3 so that the protective cap 31 may simply fall away. Thisavoids the risk of needle stick associated with conventionalarrangements due to the need for the user's hand to be placed in thevicinity of the needle tip when removing the protective cap.

FIG. 4 shows a catheter placement unit 40 both with a needle tipprotector 10 as described with reference to FIGS. 1 and 2 and aprotective cap 41 mounted on the unit by a pivoting member 42 which issimilar to the pivoting member 32 of FIG. 3 except that it is adapted toextend over the protector 10 and to engage flange formations 44 on theneedle hub 3 by means of fingers 43. FIG. 4 includes at A an end view ofthe unit 40 showing the manner in which the fingers 43 extend onopposite sides of the needle hub 3 and include projections 45 whichextend into recesses 46 in the needle hub 3. The manner in which such aprotective cap 41 is disengaged from the unit 40 to enable placement ofthe catheter in a patient's body is as previously described.

We claim:
 1. A catheter placement unit comprising a catheter (4) havingan axial bore, a catheter hub (5) at one end of the catheter (4), anintroducing needle (2) having a pointed tip (6) for introducing thecatheter (4) into a desired position in a patient's body, a needle hub(3) at the end of the needle (2) remote from the tip (6) for mountingthe needle (2) so that it extends through the catheter bore forintroduction of the catheter into the patient's body and so that it cansubsequently be withdrawn from the catheter bore leaving the catheter inposition in the patient's body, and a needle tip protector (10) on theneedle (2) for shielding the needle tip (6) when the needle has beenwithdrawn from the catheter bore, the needle tip protector (10)including a guard element (14) which is held against a resilient bias ina cocked position to one side of the catheter (4) while the catheter isintroduced into the patient's body and which, on subsequent withdrawalof the needle (2) from the catheter bore, moves laterally by resilientaction from the cocked position into a guard position shielding theneedle tip (6), the needle tip protector (10) obstructing movement ofthe catheter hub (5) along the needle (2) so as to prevent separation ofthe catheter (4) from the needle tip protector (10) until the needle (2)has been withdrawn from the catheter bore so as to thereafter triggershielding of the needle tip (6).
 2. A unit according to claim 1, whereinthe protector (10) is arranged to obstruct movement of the catheter hub(5) along the needle (2) by means of a portion of the guard element (14)which, when the guard element (14) is in its cocked position, engages aflange (9) on the catheter hub (5) so as to obstruct movement of theflange (9) beyond said portion of the guard element (14).
 3. A unitaccording to claim 1, wherein the protector (10) is coupled to theneedle hub (3) by a flexible elongate member (11) permitting movement ofthe needle hub (3) away from the protector (10) to withdraw the needle(2) from the catheter bore.
 4. A unit according to claim 3, wherein theflexible elongate member (11) is connected to the needle hub (3) bymeans of a sliding connection (12) permitting paying out of the flexibleelongate member (11) between the needle hub (3) and the protector (10)until a stop (18) on the flexible elongate member (11) is reached.
 5. Aunit according to any claim 1, wherein the protector (10) includes abody part (13) having a bore (12A) extending therethrough for passage ofthe needle (2), the guard element (14) being mounted on the body part(13) so as to be movable between its cocked and guard positions.
 6. Aunit according to claim 1 wherein the guard element (14) is a resilientelement which is held under tension in its cocked position and is movedinto its guard position under its own resilience.
 7. A unit according toclaim 1 wherein the guard element (14) is fixed at one end and has abent portion (16) at its other end for shielding the needle tip (6). 8.A unit according to claim 1 wherein the guard element (14) is mounted ona body part (13) of the protector (10) by a tensioning part (15) whichis movable from an initial position permitting positioning of theprotector (10) relative to the catheter to a tensioning position holdingthe guard element (14) under tension in its cocked position.
 9. A unitaccording to claim 8, wherein the tensioning part (15) is hingedlyconnected to the body part (13) of the protector (10) so as to bepivotable from its initial position to its tensioning position.
 10. Aunit according to claim 1 wherein a removable protective cap (41) forshielding the needle tip (6) is coupled to the needle hub (3) by acoupling part (42) which is disengageable from the needle hub (3) bypivoting to effect removal of the protective cap (41).